Retinal microvasculature changes in long-term consumption of hydroxychloroquine

Area of Science:

• Ophthalmology
• Retinal Imaging
• Pharmacology

Background:

• Hydroxychloroquine (HCQ) is widely used for autoimmune diseases.
• Long-term HCQ use can lead to retinopathy, but early detection methods are crucial.
• Optical coherence tomography angiography (OCTA) offers high-resolution imaging of retinal microvasculature.

Purpose of the Study:

• To evaluate retinal microvascular and structural changes in patients on HCQ therapy using OCTA.
• To assess the impact of HCQ treatment duration on retinal layers and vascular density.
• To identify OCTA features indicative of early HCQ retinopathy.

Main Methods:

• Prospective cross-sectional study of 59 controls and 59 HCQ-treated patients (divided by treatment duration <60 and ≥60 months).
• Comprehensive ophthalmic evaluation including spectral-domain OCTA (Optovue RTVue XR Avanti).
• Analysis of retinal layer thicknesses (IRT, MRT, ORT) and vascular densities (SVD, DVD, CVD) using ETDRS grids and generalized estimating equations (GEE).

Main Results:

• Patients on HCQ for ≥60 months showed significant reductions in foveal inner retinal thickness (IRT) and parafoveal outer retinal thickness (ORT) compared to controls.
• OCTA revealed lower foveal deep retinal vascular density (DVD) and choroidal vascular density (CVD) in the long-term HCQ group (≥60 months).
• Longer HCQ duration and cumulative dose correlated with reduced foveal superficial vascular density (SVD) and IRT, and enlarged foveal avascular zone (FAZ).

Conclusions:

• OCTA suggests progressive retinal microvascular attenuation in patients on HCQ therapy, particularly after 60 months.
• Alterations in retinal structure and vasculature can occur despite normal functional testing.
• Parafoveal DVD and FAZ changes may be key indicators for OCTA's utility in monitoring HCQ retinopathy.